Three former employers, three old 401(k)s, and a browser tab that has been open since January. Consolidating them has been on the list a while.
The impulse is sound. Fewer accounts means one allocation instead of four, beneficiary records in one place, and less that gets forgotten between now and retirement. For many people, that simplification is worthwhile.
But consolidating and choosing a destination are two separate decisions, and only one of them announces itself.
The part that looks like logistics
A rollover has three possible endpoints: leave the balance in the former employer's plan, move it into the current employer's plan, or move it into a traditional IRA at a brokerage.
The IRA option is usually the most visible. Brokerages make opening an account and requesting a transfer relatively easy. Moving the balance into a current employer's plan requires first confirming that the plan accepts incoming rollovers. Leaving it where it is requires no paperwork, but it is still a destination decision.
Old 401(k)s exist because jobs changed. The Financial Question Behind the Career Question covers the financial details that often remain unresolved after a move, and the retirement account is frequently one of them.
Who this affects
Two things have to be true at once, and neither was necessarily true when the job ended.
The first is income. For 2026, direct Roth IRA contributions phase out between $242,000 and $252,000 of modified adjusted gross income for married couples filing jointly, and between $153,000 and $168,000 for single filers. Above the top of the range, direct contributions are not available.
The second is intent. One route some higher-income taxpayers use is a nondeductible contribution to a traditional IRA followed by a conversion to a Roth. Plenty of households above the phase-out never use it and have no plans to. For them, none of what follows applies.
For the ones who do use it, or expect to, the tax result depends heavily on how much pre-tax money already sits in traditional IRAs.
One rule, plainly
For that calculation, the IRS treats all of a person's traditional IRAs, including traditional SEP and SIMPLE IRAs, as a single pool, using year-end balances together with amounts distributed or converted during the year. Employer plans, including 401(k)s, are not part of that pool. This is the pro-rata rule, and it is set out in the instructions for Form 8606.
The consequence is narrow and specific. Rolling an old 401(k) into a traditional IRA moves money from outside the pool to inside it.
What that does
With no pre-tax IRA balance, a nondeductible contribution converts with little or no taxable income. With one, every conversion draws proportionally from after-tax and pre-tax money, and the pre-tax share is taxable.
Assume there is no existing IRA basis, no intervening investment earnings, and no other IRA activity during the year. A $7,500 nondeductible contribution now sits alongside a $200,000 balance rolled over from a former employer. The total pool is $207,500, of which the after-tax portion is about 3.6 percent. Converting the $7,500 means roughly $271 comes across tax-free and about $7,229 is taxable income, in a year that was not chosen for it.
The conversion is still permitted. It simply no longer isolates the $7,500 after-tax contribution from the pre-tax balance.
That condition persists. The rolled-over balance stays in the pool until it is moved somewhere else, so every conversion after this one is calculated the same way, for as long as the strategy is in use. This is usually recoverable, since eligible pre-tax dollars can often be moved into a workplace plan later, but recovering it requires a plan that accepts them and a year in which someone thinks to check.
Worth being precise about what the cost is. The converted dollars are not lost. They land in a Roth, where qualified withdrawals can eventually be tax-free, and paying tax on a conversion is sometimes the right move on purpose. The problem is that this version was not on purpose. It produced taxable income in whatever year the paperwork happened to clear, rather than in a year selected for it.
Where the second question comes from
My view is that this goes wrong because the rollover looks administrative. People research the tax questions they already know to ask. A general question can produce a correct answer while missing the fact that decides the outcome: where the money should land.
Some people inherit more than money. They inherit a network that already knows the sequence: a parent who has done this, an accountant the family has used for twenty years, an advisor who asks about the old 401(k) before the transfer request goes in. The question arrives unprompted, from outside, because someone in the room has seen it before.
That is not a clean line between households, and it does not track wealth exactly. Some first-generation wealth builders have excellent professional networks. Some inherited-wealth households have terrible ones.
But the general pattern holds. The general advice can be reasonable, and the exception still depends on a fact about your own accounts that the advice cannot see. The gap is not analytical ability. It is that the second question needs a source, and building that source is one more thing on the list at exactly the point when the decisions start to carry weight.
My view is that this goes wrong because the rollover looks administrative. People research the tax questions they already know to ask. A general question can produce a correct answer while missing the fact that decides the outcome: where the money should land.
Before anything moves
Four things are worth knowing while the balance is still in the old plan.
Where household income sits relative to the Roth phase-out, this year and next. Whether a backdoor Roth is currently in use, or plausibly will be in the next several years. Whether the current employer's plan accepts incoming rollovers, since not all of them do and the answer determines whether a workplace plan is a viable destination. And what is already held in any traditional IRA, including traditional SEP and SIMPLE IRAs, and balances opened years ago and forgotten.
One detail that trips people up: the aggregation is individual, not household. Spouses filing jointly complete separate Forms 8606, so one spouse's IRA balance does not enter the other spouse's calculation.
The order can be decided before the transfer request goes in, while all three destinations are still available.
Common questions
Can a rollover into an IRA be reversed?
A completed rollover generally cannot be treated as though it never happened. What can sometimes be done instead is moving eligible pre-tax IRA dollars into a current employer's plan, which removes them from the pool going forward. Plans are not required to accept incoming rollovers, and only the otherwise-taxable portion of a traditional IRA can be moved this way.
Does a Roth 401(k) balance change this?
No. Designated Roth money moves to a Roth IRA or to another designated Roth account that accepts it, and Roth IRAs are not part of the pro-rata pool. It cannot go into a traditional IRA. A plan holding both pre-tax and Roth money splits accordingly.
What if a large traditional IRA already exists?
Common possibilities include moving eligible pre-tax dollars into a workplace plan, completing a taxable conversion, or deciding not to use the backdoor Roth approach. Which one fits depends on the size of the balance and what else is happening with income.
Does the timing of the conversion within the year matter?
Converting soon after contributing does not avoid the pro-rata rule. The calculation looks at the year-end value of the traditional IRA pool along with amounts distributed or converted during the year. It also means that if moving eligible IRA dollars into an employer plan is part of the strategy, it generally has to be completed before year-end to affect that year's math.
Clarity beats prediction. If you want a structure for the decisions ahead, let's talk.
D'Agaro Financial Advisory is a Registered Investment Adviser located in Virginia. Registration does not imply a certain level of skill or training. This content is for educational purposes only and is not tax, legal, or investment advice.